A high pressure rotary nozzle and tractor device is disclosed in US Patent Application Publication No. 20120205405. A high pressure fluid switching valve tractor device for use with a nozzle is also disclosed in U.S. Pat. No. 8,667,987. These publications are hereby incorporated by reference in their entirety. Such nozzles and tractor devices are particularly well suited to industrial uses where the operating parameters can be in the range of 1,000 to 40,000 psi and flow rates of 5 to 150 gpm, and when rotary nozzles are employed, rotating speeds of 10 to 1000 rpm or more may be needed.
For inspection of sewer lines and other large buried or surface piping systems there is a need for a robust mechanism for viewing such systems internally to better understand blockages, restrictions and obstructions without unearthing and breaking open the system. Several solutions to this problem have been identified. One such system places a camera on a sled at the end of a hose that has jet nozzles to propel the sled down the piping ahead of the hose. However, the hose naturally has some twist as it is advanced and retracted which tends to cause the sled to tip over. Therefore there is a swivel that is installed to allow the hose to roll while the sled stays upright. However, friction in the swivel at operating pressure apparently prevents this swivel from performing the desired function. Thus the sled upon which the camera is mounted tips over and becomes submerged in whatever fluid is within the piping, especially when trying to negotiate around bends in the piping system. The present disclosure addresses this difficulty in a new manner.